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Molar Mass Calculator

Estimate a compound's molar mass from its formula, including supported nested groups and hydrate notation.

Updated

What is the Molar Mass Calculator?

Calculate an approximate molar mass from a chemical formula. Enter element symbols, subscripts, and supported parenthesized or hydrate groups to see a total and an element-by-element breakdown.

Why Use This Tool?

  • Atomic-mass estimates: Uses a built-in table of standard atomic masses.
  • Formula parsing: Handles nested parentheses (e.g., Ca(OH)2) and supported hydrate notation (e.g., CuSO4·5H2O).
  • Instant Feedback: Live calculation as you type, with clear error messages for invalid input.
  • Element Breakdown: See the contribution of each element to the total molar mass.
  • Browser-based: Calculations are performed in your browser.

Atomic masses are rounded reference values, and the calculator does not distinguish isotopes or represent every chemical structure. Use it for learning and estimates, not as a substitute for laboratory reference data.

How it works

Step-by-Step Process

  1. Input Your Formula Enter the chemical formula in the input field. The calculator supports:
  • Element symbols (e.g., H, He, Na, Cl).
  • Subscripts for atom counts (e.g., H2O, C6H12O6).
  • Parentheses for groups (e.g., Ca(OH)2).
  • Hydration notation (e.g., CuSO4·5H2O).
  1. Live Calculation As you type, the tool parses your formula in real-time. It:
  • Validates each element symbol against the periodic table.
  • Handles nested parentheses and multipliers (e.g., (NH4)2SO4).
  • Aggregates the molar mass of all atoms in the formula.
  1. View Results
  • Total Molar Mass: An estimate from the built-in atomic-mass table.
  • Element Breakdown: A detailed list of each element, its count, and its contribution to the total mass.
  • Formula Breakdown: A parsed version of your input for verification.
  1. Copy or Share Use the Copy button to quickly copy the parsed formula or results for your notes or reports.

Example Walkthrough

For the formula Ca(OH)2:

  • Calcium (Ca): 1 atom × 40.078 g/mol = 40.078 g/mol
  • Oxygen (O): 2 atoms × 15.999 g/mol = 31.998 g/mol
  • Hydrogen (H): 2 atoms × 1.008 g/mol = 2.016 g/mol
  • Total Molar Mass: 40.078 + 31.998 + 2.016 = 74.092 g/mol

The tool reports errors such as unknown elements or unmatched parentheses. Its output is based on the formula entered, not a validation of the compound's identity or structure.

Examples

Water

Calculate the molar mass of water (H2O).

H2O
 
18.015 g/mol

Glucose

Calculate the molar mass of glucose (C6H12O6).

C6H12O6
 
180.156 g/mol

Calcium Hydroxide

Calculate the molar mass of calcium hydroxide (Ca(OH)2).

Ca(OH)2
 
74.093 g/mol

Copper Sulfate Pentahydrate

Calculate the molar mass of copper sulfate pentahydrate (CuSO4·5H2O).

CuSO4·5H2O
 
249.682 g/mol

Frequently asked questions

What is molar mass?

Molar mass is the mass of one mole of a substance, expressed in grams per mole (g/mol). It is calculated by summing the atomic masses of all the atoms in a chemical formula.

How do I use the Molar Mass Calculator?

Simply type the chemical formula into the input field. The calculator will automatically compute the molar mass and display the result, along with a breakdown of each element's contribution.

Does the calculator support parentheses and nested groups?

Yes! The calculator fully supports parentheses and nested groups. For example, you can input formulas like Ca(OH)2 or Al2(SO4)3 and it will correctly interpret the grouping and multipliers.

Can I calculate the molar mass of hydrated compounds?

Absolutely. The calculator recognizes hydration notation (e.g., CuSO4·5H2O). The dot (·) is treated as a separator, and the water molecules are included in the total molar mass calculation.

What if I enter an invalid element symbol?

The calculator will display an error message indicating that the element is unknown. For example, entering H2X will result in an error because "X" is not a valid element symbol.

Are the atomic masses up to date?

The calculator uses a built-in table of rounded atomic-mass values. It is not a live or authoritative periodic-table database; consult a current reference when precision matters.

Can I use this tool for organic compounds?

Yes! The calculator works for all types of chemical compounds, including organic molecules like C6H12O6 (glucose) or C8H18 (octane).

Does the calculator handle isotopes or custom atomic masses?

Currently, the calculator uses standard atomic masses for each element. It does not support custom atomic masses or isotopes. For most educational and professional purposes, the standard values are sufficient.

How accurate are the results?

The result is an estimate based on the rounded atomic masses in the tool. It does not account for isotope composition, purity, or the specific form of a substance. Check a suitable reference for laboratory work.

Is there a limit to the complexity of the formula I can input?

The parser supports nested groups and the hydrate notation described in the instructions. It is not a general chemical-structure validator, and unsupported formula syntax may be rejected.

Can I use this tool offline?

Calculations run in your browser after the page is loaded. Whether the page can be reopened offline depends on your browser's cache.

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